This invention relates to N-aroyl cyclic amine derivatives and their use as pharmaceuticals.
Many medically significant biological processes are mediated by proteins participating in signal transduction pathways that involve G-proteins and/or second messengers.
Polypeptides and polynucleotides encoding the human 7-transmembrane G-protein coupled neuropeptide receptor, orexin-1 (HFGAN72), have been identified and are disclosed in EP-A-875565, EP-A-875566 and WO 96/34877. Polypeptides and polynucleotides encoding a second human orexin receptor, orexin-2 (HFGANP), have been identified and are disclosed in EP-A-893498.
Polypeptides and polynucleotides encoding polypeptides which are ligands for the orexin-1 receptor, e.g. orexin-A (Lig72A) are disclosed in EP-A-849361.
Orexin receptors are found in the mammalian host and may be responsible for many biological functions, including pathologies including, but not limited to, depression; anxiety; addictions; obsessive compulsive disorder; affective neurosis/disorder, depressive neurosis/disorder; anxiety neurosis; dystymic disorder; behaviour disorder; mood disorder; sexual dysfunction; psychosexual dysfunction; sex disorder; sexual disorder; schizophrenia; manic depression; delerium; dementia; severe mental retardation and dyskinesias such as Huntington""s disease and Gilles de la Tourett""s syndrome; disturbed biological and circadian rhythms; feeding disorders, such as anorexia, bulimia, cachexia, and obesity; diabetes; appetite/taste disorders; vomiting/nausea; asthma; cancer; Parkinson""s disease; Cushing""s syndrome/disease; basophil adenoma; prolactinoma; hyperprolactinemia; hypopituitarism; hypophysis tumor/adenoma; hypothalamic diseases; Froehlich""s syndrome; adrenohypophysis disease; hypophysis disease; hypophysis tumor/adenoma; pituitary growth hormone; adrenohypophysis hypofunction; adrenohypophysis hyperfunction; hypothalamic hypogonadism; Kallman""s syndrome (anosmia, hyposmia); functional or psychogenic amenorrhea; hypopituitarism; hypothalamic hypothyroidism; hypothalamic-adrenal dysfunction; idiopathic hyperprolactinemia; hypothalamic disorders of growth hormone deficiency; idiopathic growth hormone deficiency; dwarfism; gigantism; acromegaly; disturbed biological and circadian rhythms; and sleep disturbances associated with such diseases as neurological disorders, neuropathic pain and restless leg syndrome, heart and lung diseases; acute and congestive heart failure; hypotension; hypertension; urinary retention; osteoporosis; angina pectoris; myocardial infarction; ischaemic or haemorrhagic stroke; subarachnoid haemorrhage; head injury such as sub-arachnoid haemorrhage associated with traumatic head injury; ulcers; allergies; benign prostatic hypertrophy; chronic renal failure; renal disease; impaired glucose tolerance; migraine; hyperalgesia; pain; enhanced or exaggerated sensitivity to pain, such as hyperalgesia, causalgia and allodynia; acute pain; burn pain; atypical facial pain; neuropathic pain; back pain; complex regional pain syndromes I and II; arthritic pain; sports injury pain; pain related to infection, e.g. HIV, post-polio syndrome, and post-herpetic neuralgia; phantom limb pain; labour pain; cancer pain; post-chemotherapy pain; post-stroke pain; post-operative pain; neuralgia; conditions associated with visceral pain including irritable bowel syndrome, migraine and angina; urinary bladder incontinence e.g. urge incontinence; tolerance to narcotics or withdrawal from narcotics; sleep disorders; sleep apnea; narcolepsy; insomnia; parasomnia; jet-lag syndrome; and neurodegenerative disorders, which includes nosological entities such as disinhibition-dementia-parkinsonism-amyotrophy complex; pallido-ponto-nigral degeneration, epilepsy, and seizure disorders.
Experiments have shown that central administration of the ligand orexin-A (described in more detail below) stimulated food intake in freely-feeding rats during a 4 hour time period. This increase was approximately four-fold over control rats receiving vehicle. These data suggest that orexin-A may be an endogenous regulator of appetite. Therefore, antagonists of its receptor may be useful in the treatment of obesity and diabetes, see Cell, 1998, 92, 573-585.
There is a significant incidence of obesity in westernised societies According to WHO definitions a mean of 35% of subjects in 39 studies were overweight and a further 22% clinically obese. It has been estimated that 5.7% of all healthcare costs in the USA are a consequence of obesity. About 85% of Type 2 diabetics are obese, and diet and exercise are of value in all diabetics. The incidence of diagnosed diabetes in westernised countries is typically 5% and there are estimated to be an equal number undiagnosed. The incidence of both diseases is rising, demonstrating the inadequacy of current treatments which may be either ineffective or have toxicity risks including cardiovascular effects. Treatment of diabetes with sulfonylureas or insulin can cause hypoglycaemia, whilst metformin causes GI side-effects. No drug treatment for Type 2 diabetes has been shown to reduce the long-term complications of the disease. Insulin sensitisers will be useful for many diabetics, however they do not have an anti-obesity effect.
Rat sleep/EEG studies have also shown that central administration of orexin-A, an agonist of the orexin receptors, causes a dose-related increase in arousal, largely at the expense of a reduction in paradoxical sleep and slow wave sleep 2, when administered at the onset of the normal sleep period. Therefore antagonists of its receptor may be useful in the treatment of sleep disorders including insomnia.
International Patent Applications WO99/09024, WO99/58533, WO00/47577 and WO00/47580 disclose phenyl urea derivatives and WO00/47576 discloses quinolinyl cinnamide derivatives as orexin receptor antagonists.
The present invention provides N-aroyl cyclic amine derivatives which are non-peptide antagonists of human orexin receptors, in particular orexin-1 receptors. In particular, these compounds are of potential use in the treatment of obesity, including obesity observed in Type 2 (non-insulin-dependent) diabetes patients, and/or sleep disorders.
According to the invention there is provided a compound of formula (I): 
wherein:
Y represents a group (CH2)n, wherein n represents 0, 1 or 2;
R1 is phenyl, naphthyl, a mono or bicyclic heteroaryl group containing up to 3 heteroatoms selected from N, O and S; or a group NR3R4 wherein one of R3 and R4 is hydrogen or optionally substituted (C1-4)alkyl and the other is phenyl, naphthyl or a mono or bicyclic heteroaryl group containing up to 3 heteroatoms selected from N, O and S, or R3 and R4 together with the N atom to which they are attached form a 5 to 7-membered cyclic amine which has an optionally fused phenyl ring; any of which R1 groups may be optionally substituted;
R2 represents phenyl or a 5- or 6-membered heteroaryl group containing up to 3 heteroatoms selected from N, O and S, wherein the phenyl or heteroaryl group is substituted by R5, and further optional substituents; or R2 represents an optionally substituted bicyclic aromatic or bicyclic heteroaromatic group containing up to 3 heteroatoms selected from N, O and S;
R5 represents an optionally substituted (C1-4)alkoxy, halo, optionally substituted (C1-6)alkyl, optionally substituted phenyl, or an optionally substituted 5- or 6-membered heterocyclic ring containing up to 3 heteroatoms selected from N, O and S;
or a pharmaceutically acceptable salt thereof.
Y is preferably (CH2)n wherein n is 1.
A specific group of compounds which may be mentioned are those in which R1 is phenyl, naphthyl or a mono or bicyclic heteroaryl group containing up to 3 heteroatoms selected from N, O and S; any of which may be optionally substituted. Preferably R1 is an optionally substituted phenyl or benzofuranyl. The phenyl group may have up to 5, preferably 1, 2 or 3 optional substituents.
When R1 is a group NR3R4 preferably one of R3 and R4 is optionally substituted phenyl. The phenyl group may have up to 5, preferably 1, 2 or 3 optional substituents.
Examples of groups where R1 or one of R3 and R4 is a mono or bicyclic heteroaryl group containing up to 3 heteroatoms selected from N, O and S, include pyridyl, furanyl, indolyl, benrzofuranyl, quinolinyl, isoquinolinyl, pyrazinyl, quinoxalinyl, benzoxazolyl, pyrazolyl, isoxazolyl, azaindolyl, indazolyl or naphthyridinyl. An alternative group is pyridyl, furayl, indolyl, benzofuranyl, quinolinyl, isoquinolinyl, pyrazinyl and quinoxalinyl. Most preferably R1 is optionally substituted phenyl or benzofuranyl.
When R3 and R4 together with the N atom to which they are attached form a 5 to 7-membered cyclic amine which has an optionally fused phenyl ring said group is preferably an indolinyl moiety optionally substituted by fluoro, chloro, cyano, methyl, trifluoromethyl, methoxy or trifluoromethoxy.
Preferably where R2 represents phenyl or a heteroaryl group the R5 group is situated adjacent to the point of attachment to the amide carbonyl.
Examples of groups where R2 represents a 5- or 6-membered heteroaryl group containing up to 3 heteroatoms selected from N, O and S, include thiazolyl, pyrazolyl, triazolyl, pyridazyl isoxazolyl, and thiophenyl.
Preferably R2 represents optionally substituted phenyl, thiazolyl, pyrazolyl, 1,2,3-triazolyl, pyridazyl, isoxazolyl, or thiophenyl. R2 may represent optionally substituted phenyl,thiazolyl, pyrazoly, 1,2,3-triazolyl, pyridazyl or isoxazolyl.
Examples of groups where R5 is a 5- or 6-membered heterocyclyl group containing up to 3 heteroatoms selected from N, O and S, include furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, pyridyl, triazolyl, triazinyl, pyridazyl, pyrimidinyl, isothiazolyl, isoxazolyl, pyrazinyl, pyrazolyl or pyrimidinyl.
More preferably R5 may represent a trifluoromethoxy group, halo, (C4-6)alkyl, optionally substituted phenyl or an optionally substituted 5- or 6-membered heterocyclic ring containing up to 3 heteroatom selected from N, O, S.
Even more preferably R5 represents an optionally substituted phenyl,pyridyl, oxadiazolyl, furanyl, pyrimidinyl or methoxy group.
Most preferably R5 is selected from trifluoromethoxy, methoxy, halo, or an optionally substituted phenyl, pyridyl, pyrazolyl or oxadiazolyl group.
Optional substituents for the groups R1 to R5 include halogen, hydroxy, oxo, cyano, nitro, (C1-4)alkyl, (C1-4)alkoxy, halo(C1-4)alkyl, halo(C1-4)alkoxy, aryl(C1-4)alkoxy, (C1-4)alkylthio, hydroxy(C1-4)alkyl, (C1-4)alkoxy(C1-4)alkyl, (C3-6)cycloalkyl(C1-4)alkoxy, (C1-4)alkanoyl, (C1-4)alkoxycarbonyl, (C1-4)alkylsulfonyl, (C1-4)alkylsulfonyloxym, (C1-4)alkylsulfonyl(C1-4)alkyl, arylsulfonyl, arylsulfonyloxy, arylsulfonyl(C1-4)alkyl, (C1-4)alkylsulfonamido, (C1-4)alkylamido, (C1-4)alkylsulfonamido(C1-4)alkyl, (C1-4)alkylamido(C1-4)alkyl, arylsulfonamido, arylcarboxamido, arylsulfonamido(C1-4)alkyl, arylcarboxamido(C1-4)alkyl, aroyl, aroyl(C1-4)alkyl, or aryl(C1-4)alkanoyl group; a group RaRbNxe2x80x94, RaOCO(CH2)r, RaCON(R4)(CH2)r, RaRbNCO(CH2)r, RaRbNSO2(CH2)r or RaSO2NRb(CH2)r where each of Ra and Rb independently represents a hydrogen atom or a (C1-4)alkyl group or where appropriate RaRb forms part of a (C3-6)azacyloalkane or (C3-6)(2-oxo)azacycloalkane ring and r represents zero or an integer from 1 to 4. Alternative substitiuents include hydroxy(C1-4)alkyl, and hydroxy(C2-4)alkoxy.
In addition R1 may be optionally substituted by a phenyl ring optionally substituted by a halogen, cyano or (C1-4)alkanoyl; or by a 5- or 6-membered heterocyclic ring, optionally substituted by a (C1-2)alkyl or RaRbNxe2x80x94 group; wherein Ra and Rb are as defined above.
Preferred optional substituents for R2 are halogen, cyano, optionally substituted (C1-6)alkyl, optionally substituted (C1-6)alkoxy, or RaRbNxe2x80x94 wherein Ra and Rb independently represent a hydrogen atom or a (C1-4)alkyl group.
In the groups R1 to R5, substituents positioned ortho to one another may be linked to form a ring.
When a halogen atom is present in the compound of formula (I) it may be fluorine, chlorine, bromine or iodine.
When the compound of formula (I) contains an alkyl group, whether alone or forming part of a larger group, e.g. alkoxy or allylthio, the alkyl group may be straight chain, branched or cyclic, or combinations thereof, it is preferably methyl or ethyl.
It will be appreciated that compounds of formula (I) may exist as R or S enantiomers. The present invention includes within its scope all such isomers, including mixtures. Where additional chiral centres are present in compounds of formula (I), the present invention includes within its scope all possible diastereoismers, including mixtures thereof. The different isomeric forms may be separated or resolved one from the other by conventional methods, or any given isomer may be obtained by conventional synthetic methods or by stereospecific or asymmetric syntheses.
It will be understood that the invention includes pharmaceutically acceptable derivatives of compounds of formula (I) and that these are included in the scope of the invention.
As used herein xe2x80x9cpharmaceutically acceptable derivativexe2x80x9d includes any pharmaceutically acceptable salt or ester or salt of such ester of a compound of formula (I) or which upon administration to the recipient is capable of providing (directly or indirectly) a compound of formula (I) or an active metabolite thereof.
Particular compounds according to the invention include those mentioned in the examples and their pharmaceutically acceptable salts.
It will be appreciated that for use in medicine the salts of thecompounds of formula (I) should be pharmaceutically acceptable. Suitable pharmaceutically acceptable salts will be apparent to those skilled in the art and include acid addition salts formed with inorganic acids e.g. hydrochloric, hydrobromic, sulphuric, nitric or phosphoric acid; and organic acids e.g. succinic, maleic, acetic, fuimaric, citric, tartaric, benzoic, p-toluenesulfonic, methanesulfonic or naphthalenesulfonic acid. Other salts e.g. oxalates, may be used, for example in the isolation of compounds of formula (I) and are included within the scope of this invention. Also included within the scope of the invention are solvates and hydrates of compounds of formula (I).
Certain of the compounds of formula (I) may form acid addition salts with one ormore equivalents of the acid. The present invention includes within its scope all possible stoichiometric and non-stoichiometric forms.
Since the compounds of formula (I) are intended for use in pharmaceutical compositions it will readily be understood that they are each preferably provided in substantially pure forms for example at least 60% pure, more suitably at least 75% pure and preferably at least 85%, especially at least 98% pure (% are on a weight for weight basis). Impure preparations of the compounds may be used for preparing the more pure forms used in the pharmaceutical compositions.
According to a further feature of the invention there is provided a process for the preparation of compounds of formula (I) and salts thereof. The following schemes detail synthetic routes to compounds of the invention. 
wherein Y and R2 are as defined for formula (I), R1 is phenyl, naphthyl, or a mono or bicyclic heteroaryl group containing up to 3 heteroatoms selected from N, O and S, which groups may be optionally substituted, P is a protecting group and L1 and L2 are leaving groups.
Examples of protecting groups P include t-butyloxycarbonyl, trifluoroacetyl, benzyloxycarbonyl and optionally substituted benzyl. Deprotection conditions, step (ii), will depend on the particular protecting group; for the groups mentioned above these are respectively, acid (e.g. trifluoroacetic acid in dichloromethane), base (e.g. potassium carbonate in a solvent such as aqueous methanol) and catalytic hydrogenolysis in an inert solvent (e.g. using palladium on charcoal in a lower alcohol or ethyl acetate).
Examples of suitable leaving groups L1 and L2 include halogen, hydroxy, OC(xe2x95x90O)alkyl OC(xe2x95x90O)O-alkyl and OSO2Me. Steps (i) and (iii) may be carried out using a wide range of known acylation conditions, e.g. in an inert solvent such as dichloromethane, in the presence of a base such as triethylamine. Alternatively these steps may be carried out when L1 or L2 represents hydroxy, in which case the reaction takes place in an inert solvent such as dichloromethane in the presence of a diimide reagent such as 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and an activator such as 1-hydroxybenzotriazole. 
wherein Y, R2, R3 and R4 are as defined for formula (I), P is a protecting group as described for Scheme 1 and L2 is a leaving group as described for Scheme 1. Formation of the urea bond, step (iv), may be carried out using methods know to those skilled in the art. For example, in an inert solvent such as dichloromethane by use of a suitable isocyanate reagent, either directly or generated in situ from a suitable acid, or acid derivative, and an azide reagent such as diphenyl phosphoryl azide. Step (iv) may also be achieved by reaction with a carbamoyl chloride reagent either directly, or generated in situ from suitable amines with reagents such as phosgene or triphosgene. Alternatively this reaction may be carried out with a suitable amine in an inert solvent in the presence of dicarbonyl reagents such as 1,1xe2x80x2-dicarbonyldiimidazole. Step (vi) may be achieved using a wide range of acylation conditions as described for Scheme 1. 
wherein Y, R1, R2, R3 and R4 are as defined for formula (I), P and P1 are amino protecting groups as described for Scheme 1 and L1 and L2 are leaving groups as described for Scheme 1.
Examples of protecting groups P and P1 include t-butyloxycarbonyl, trifluoroacetyl, benzyloxycarbonyl and optionally substituted benzyl. Deprotection conditions, step (x), will depend on the particular protecting group; for the groups mentioned above these are respectively, acid (e.g. trifluoroacetic acid in dichloromethane), base (e.g. potassium carbonate in a solvent such as aqueous methanol) and catalytic hydrogenolysis in an inert solvent (e.g. using palladium on charcoal in a lower alcohol or ethyl acetate). In scheme 3, protecting groups P and P1 are selected to be different. Step (xii) can be carried out as described for step (iv) in Scheme 2. 
wherein Y and R2 are as defined for formula (I), R1 is phenyl, naphthyl, or a mono or bicyclic heteroaryl group containing up to 3 heteroatoms selected from N, O and S which groups may be optionally substituted and L1 and L2 are leaving groups as described for Scheme 1.
Compound (A) may be prepared as described in O. Froelich et al., Tet. Asym. 1993, 4 (11), 2335 and references therein. 
wherein Y, R2, R3 and R4 are as defined for formula (I), and L2 is a leaving group as described for Scheme 1. Step (xix) can be carried out as described for step (iv) in Scheme 2.
The starting materials for use in Schemes 1 to 5 are commercially available, known in the literature or can be prepared by known methods. Within the schemes above there is scope for functional group interconversion.
The compounds of formula (I) may be prepared singly or as compound libraries comprising at least 2, e.g. 5 to 1000, preferably 10 to 100 compounds of formula (I). Compound libraries may be prepared by a combinatorial xe2x80x98split and mixxe2x80x99 approach or by multiple parallel synthesis using either solution phase or solid phase chemistry, by procedures known to those skilled in the art.
Thus according to a further aspect of the invention there is provided a compound library comprising at least 2 compounds of formula (I), or pharmaceutically acceptable salts thereof.
Pharmaceutically acceptable salts may be prepared conventionally by reaction with the appropriate acid or acid derivative.
The compounds of formula (I) and their pharmaceutically acceptable derivatives are useful for the treatment of diseases or disorders where an antagonist of a human orexin receptor is required such as obesity and diabetes; prolactinoma; hypoprolactinemia; hypothalamic disorders of growth hormone deficiency; idiopathic growth hormone deficiency; Cushings syndrome/disease; hypothalamic-adrenal dysfunction; dwarfism; sleep disorders; sleep apnea; narcolepsy; insomnia; parasomnia; jet-lag syndrome; sleep disturbances associated with diseases such as neurological disorders, neuropathic pain and restless leg syndrome; heart and lung diseases; depression; anxiety; addictions; obsessive compulsive disorder; affective neurosis/disorder; depressive neurosis/disorder; anxiety neurosis; dysthymic disorder; behaviour disorder; mood disorder; sexual dysfunction; psychosexual dysfunction; sex disorder; sexual disorder; schizophrenia; manic depression; delerium; dementia; bulimia and hypopituitarism.
The compounds of formula (I) and their pharmaceutically acceptable derivatives are particularly useful for the treatment of obesity, including obesity associated with Type 2 diabetes, and sleep disorders.
Other diseases or disorders which may be treated in accordance with the invention include disturbed biological and circadian rhythms; adrenohypophysis disease; hypophysis disease; hypophysis tumor/adenoma; adrenohypophysis hypofunction; functional or psychogenic amenorrhea; adrenohypophysis hyperfunction; migraine; hyperalgesia; pain; enhanced or exaggerated sensitivity to pain such as hyperalgesia, causalgia and allodynia; acute pain; burn pain; atypical facial pain; neuropathic pain; back pain; complex regional pain syndromes I and II; arthritic pain; sports injury pain; pain related to infection e.g. HIV, post-polio syndrome and post-herpetic neuralgia; phantom limb pain; labour pain; cancer pain; post-chemotherapy pain; post-stroke pain; post-operative pain; neuralgia; and tolerance to narcotics or withdrawal from narcotics.
The invention also provides a method of treating or preventing diseases or disorders where an antagonist of a human orexin receptor is required, which comprises administering to a subject in need thereof an effective amount of a compound of formula (I), or a pharmaceutically acceptable derivative thereof.
The invention also provides a compound of formula (I), or a pharmaceutically acceptable derivative thereof, for use in the treatment or prophylaxis of diseases or disorders where an antagonist of a human orexin receptor is required.
The invention also provides the use of a compound of formula (I), or a pharmaceutically acceptable derivative thereof, in the manufacture of a medicament for the treatment or prophylaxis of diseases or disorders where an antagonist of a human orexin receptor is required.
For use in therapy the compounds of the invention are usually administered as a pharmaceutical composition. The invention also provides a pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically acceptable derivative thereof, and a pharmaceutically acceptable carrier.
The compounds of formula (I) and their pharmaceutically acceptable derivatives may be administered by any convenient method, e.g. by oral, parenteral, buccal, sublingual, nasal, rectal or transdermal administration, and the pharmaceutical compositions adapted accordingly.
The compounds of formula (I) and their pharmaceutically acceptable derivatives which are active when given orally can be formulated as liquids or solids, e.g. as syrups, suspensions, emulsions, tablets, capsules or lozenges.
A liquid formulation will generally consist of a suspension or solution of the active ingredient in a suitable liquid carrier(s) e.g. an aqueous solvent such as water, ethanol or glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring and/or colouring agent.
A composition, in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations, such as magnesium stearate, starch, lactose, sucrose and cellulose.
A composition in the form of a capsule can be prepared using routine encapsulation procedures, e.g. pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), e.g. aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule.
Typical parenteral compositions consist of a solution or suspension of the active ingredient in a sterile aqueous carrier or parenterally acceptable oil, e.g. polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration.
Compositions for nasal administration may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations typically comprise a solution or fine suspension of the active ingredient in a pharmaceutically acceptable aqueous or non-aqueous solvent and are usually presented in single or multidose quantities in sterile form in a sealed container which can take the form of a cartridge or refill for use with an atomising device. Alternatively the sealed container may be a disposable dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve. Where the dosage form comprises an aerosol dispenser, it will contain a propellant which can be a compressed gas e.g. air, or an organic propellant such as a fluorochloro-hydrocarbon or hydrofluorocarbon. Aerosol dosage forms can also take the form of pump-atomisers.
Compositions suitable for buccal or sublingual administration include tablets, lozenges and pastilles where the active ingredient is formulated with a carrier such as sugar and acacia, tragacanth, or gelatin and glycerin.
Compositions for rectal administration are conveniently in the form of suppositories containing a conventional suppository base such as cocoa butter.
Compositions suitable for transdermal administration include ointments, gels and patches.
Preferably the composition is in unit dose form such as a tablet, capsule or ampoule.
The dose of the compound of formula (I), or a pharmaceutically acceptable derivative thereof, used in the treatment or prophylaxis of the abovementioned disorders or diseases will vary in the usual way with the particular disorder or disease being treated, the weight of the subject and other similar factors. However, as a general rule, suitable unit doses may be 0.05 to 1000 mg, more suitably 0.05 to 500 mg. Unit doses may be administered more than once a day for example two or three times a day, so that the total daily dosage is in the range of about 0.01 to 100 mg/kg; and such therapy may extend for a number of weeks or months. In the case of pharmaceutically acceptable derivatives the above figures are calculated as the parent compound of formula (I).
No toxicological effects are indicated/expected when a compound of formula (I) is administered in the above mentioned dosage range.
Human orexin-A has the amino acid sequence:
Orexin-A can be employed in screening procedures for compounds which inhibit the ligand""s activation of the orexin-1 receptor.
In general, such screening procedures involve providing appropriate cells which express the orexin-1 receptor on their surface. Such cells include cells from mammals, yeast, Drosophila or E. coli. In particular, a polynucleotide encoding the orexin-1 receptor is used to transfect cells to express the receptor. The expressed receptor is then contacted with a test compound and an orexin-1 receptor ligand to observe inhibition of a functional response. One such screening procedure involves the use of melanophores which are transfected to express the orexin-1 receptor, as described in WO 92/01810.
Another screening procedure involves introducing RNA encoding the orexin-1 receptor into Xenopus oocytes to transiently express the receptor. The receptor oocytes are then contacted with a receptor ligand and a test compound, followed by detection of inhibition of a signal in the case of screening for compounds which are thought to inhibit activation of the receptor by the ligand.
Another method involves screening for compounds which inhibit activation of the receptor by determining inhibition of binding of a labelled orexin-1 receptor ligand to cells which have the receptor on their surface. This method involves transfecting a eukaryotic cell with DNA encoding the orexin-1 receptor such that the cell expresses the receptor on its surface and contacting the cell or cell membrane preparation with a compound in the presence of a labelled form of an orexin-1 receptor ligand. The ligand may contain a radioactive label. The amount of labelled ligand bound to the receptors is measured, e.g. by measuring radioactivity.
Yet another screening technique involves the use of FILIPR equipment for high throughput screening of test compounds that inhibit mobilisation of intracellular calcium ions, or other ions, by affecting the interaction of an orexin-1 receptor ligand with the orexin-1 receptor.
All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.